1. Field of the Invention
The present invention pertains to surgical instruments for precisely positioning guide wires in bone allowing tunnels to be formed in the bone along the guide wires and, more particularly, to femoral guides for precisely positioning guide wires in the femur in cruciate ligament reconstruction of the knee allowing bone tunnels to be formed in the femur along the guide wires at sites anatomically equivalent to the cruciate ligament and to methods of precisely forming bone tunnels.
2. Description of the Prior Art
Various surgical procedures utilize graft or prosthetic ligaments to reconstruct natural ligaments that have been damaged by injury or disease. Where the ligaments to be reconstructed are found in joints or articulations of the body, i.e., the connections of the various surfaces of the bones in the body, graft or prosthetic ligaments are typically implanted and fixated in bones of the joint at sites anatomically equivalent to the natural ligament. In cruciate ligament reconstruction, such as anterior cruciate ligament reconstruction of the knee, tandem, isometrically positioned bone tunnels are formed, respectively, in the tibia and femur at sites anatomically equivalent to attachment of the anterior cruciate ligament, and a graft or prosthetic ligament having bone blocks at its ends is inserted in the bone tunnels to extend across the knee joint with the bone blocks disposed, respectively, in the bone tunnels. Interference bone fixation screws are inserted in the tibial and femoral bone tunnels to be positioned laterally between the bone blocks and walls of the bone tunnels to fixate the ligament and provide a bone-tendon-bone graft. In anterior cruciate ligament reconstruction of the knee, it is very important that the bone tunnels be located at the anatomic sites of attachment of the anterior cruciate ligament; and, where anterior cruciate ligament reconstruction is performed as an open surgical procedure utilizing relatively long incisions on the order of ten inches in length to access the knee joint, the increased room for maneuverability afforded by the long incisions can enhance proper placement of the tibial and femoral bone tunnels. However, open surgery possesses numerous disadvantages over closed, or least invasive surgery, including increased invasiveness and trauma, prolonged hospitalization and rehabilitation times, increased patient discomfort, possible violation of capsular mechanoreceptors, dessication of articular cartilage and delayed post-surgical mobility. Accordingly, it is preferred to perform anterior cruciate ligament reconstruction as a least invasive, closed, or endoscopic, procedure wherein portals of minimal size, such as are formed with a puncture or stab wound, in tissue adjacent the knee are utilized to access the knee joint with the knee being visualized with an arthroscope, the portals being just large enough to accommodate surgical instruments inserted at the knee joint. Arthroscopic anterior cruciate ligament reconstruction provides numerous benefits over open surgery including minimal invasiveness and trauma, performance on an out-patient basis, reduced rehabilitation time, decreased patient discomfort, early, aggressive range of motion, cosmetically pleasing incisions, completion with tourniquet times under one hour, the opportunity to perform a diagnostic arthroscopy without having to commit to anterior cruciate ligament reconstruction unless confirmed by the diagnostic findings and early weight bearing without loss of fixation.
Where cruciate ligament reconstruction is performed as a closed, or endoscopic, surgical procedure, the small size of the portals limits access to and maneuverability at the knee joint making it relatively more difficult to precisely place the tibial and femoral bone tunnels at sites anatomically equivalent to the cruciate ligament. In most cases, guide wires or pins are inserted through arthroscopic size portals from externally of the body and are driven, from externally of the body, in the tibia and femur at desired locations for longitudinal axes, or centers, of the tibial and femoral bone tunnels, allowing the bone tunnels to be formed along the guide wires, such as by drilling or reaming, substantially coaxially or concentrically with the guide wires. Although the guide wires are effective in guiding instruments, such as drills and reamers, utilized to form the bone tunnels, problems can arise in arthroscopic cruciate ligament reconstruction in precisely positioning or locating the guide wires. If the guide wires are not located and inserted at sites anatomically equivalent to attachment of the cruciate ligament, the tibial and femoral bone tunnels, as guided by the guide wires, will not be properly located, and ligament reconstruction will be impaired. In arthroscopic anterior cruciate ligament reconstruction, it is difficult to position a guide wire on the femur at a position corresponding to the anatomic center of attachment of the anterior cruciate ligament. In order to position a tip of the guide wire on the femoral condyle at the anatomic center for the anterior cruciate ligament and drive the guide wire into the femur such that a bone tunnel formed along the guide wire will have a longitudinal axis substantially aligned with the anatomic center of the anterior cruciate ligament, the guide wire must be inserted through a tibial bone tunnel from a portal of minimal size, and a tip of the guide wire must be located on the femoral condyle with the guide wire held and driven into the femur from externally of the knee. When positioning the tip of the guide wire on the femoral condyle, it is desired that the tip be positioned high in a notch on the femoral condyle, the notch being formed in a notchplasty procedure prior to formation of the bone tunnels, such that the longitudinal axis of the femoral bone tunnel will be disposed sufficiently anterior, i.e., approximately 6-7 millimeters, to the posterior edge or xe2x80x9cover-the-top ridgexe2x80x9d of the notch and the femoral bone tunnel will be as far posterior as possible while still allowing a tunnel and not a trough with the cortical margin of the femur being neither too wide nor too narrow. However, it is extremely difficult in arthroscopic anterior cruciate ligament reconstruction to position and hold the guide wire from externally of the knee such that the tip of the guide wire is optimally, isometrically positioned on the femur; and, even when properly positioned, the guide wire can slip or shift prior to being driven into the femur resulting in an improperly positioned femoral bone tunnel and impaired placement of the graft or prosthetic ligament. Where instruments are used to help guide or hold the guide wire, the instruments themselves can slip or shift causing displacement of the guide wire; and, frequently, the use of instruments does not eliminate the need for a surgeon to estimate where to place instruments such as drills or reamers when forming the femoral bone tunnel along the guide wire. Accordingly, arthroscopic anterior cruciate ligament reconstruction as presently performed lacks instruments for precisely positioning a guide wire on the femur at a site anatomically equivalent to the anterior cruciate ligament to allow a femoral bone tunnel formed substantially coaxially or concentrically along the guide wire to be optimally, isometrically positioned.
Accordingly, it is a primary object of the present invention to overcome the above-mentioned disadvantages of femoral guides and methods of forming bone tunnels.
Another object of the present invention is to provide a guide for precisely positioning a guide wire on a bone surface in relation to a reference edge on the bone surface engaged by the guide.
A further object of the present invention is to provide a femoral guide for precisely positioning a guide wire in the femur such that a bone tunnel formed along the guide wire has a longitudinal axis substantially aligned with the anatomic center of attachment of the cruciate ligament.
It is also an object of the present invention to provide a guide having a tongue for engaging an edge on a bone surface to position a guide wire inserted through the guide on the bone surface such that a longitudinal axis of a tunnel formed substantially concentrically along the guide wire is a predetermined distance from the edge.
Yet another object of the present invention is to provide a femoral guide having a tongue and a lumen having a longitudinal axis disposed a predetermined distance from the tongue such that a guide wire inserted in the lumen has a longitudinal axis disposed substantially the predetermined distance from the tongue.
A still further object of the present invention is to provide a femoral guide for precisely positioning a guide wire on the femur such that a bone tunnel formed along the guide wire has a longitudinal axis approximately 6-7 millimeters anterior to a posterior edge or xe2x80x9cover-the-top ridgexe2x80x9d of a notch on the femoral condyle.
An additional object of the present invention is to provide a guide having a stylus for being driven into the bone to stabilize the guide during insertion of a guide wire into the bone along the guide.
Furthermore, it is an object of the present invention to provide a method of precisely forming bone tunnels in a joint of the body endoscopically with a guide inserted at the joint from a portal of minimal size to position a guide wired, on a surface of a bone of the joint such that the guide wire is a predetermined distance from a reference edge on the bone surface engaged by the guide allowing the guide wire to be driven into the bone for forming a bone tunnel along the guide wire.
Another object of the present invention is to provide a method of forming bone tunnels in a bone of a joint of the body endoscopically with a guide inserted at the joint from a portal of minimal size and including positioning a tongue of the guide against an edge of a bone surface of the bone such that a guide wire inserted through a lumen of the guide is positioned on the bone surface a distance from the edge that is substantially equal to the distance from the tongue to a longitudinal axis of the lumen.
It is also an object of the present invention to provide a method of forming a femoral bone tunnel in arthroscopic cruciate ligament reconstruction of the knee including the steps of inserting a femoral guide through a tibial bone tunnel from an arthroscopic size portal, positioning a tongue of the femoral guide against a posterior edge of a surface of the femoral condyle, inserting a guide wire through a lumen of the femoral guide to contact the surface of the femoral condyle and driving the guide wire into the femur such that a bone tunnel formed substantially concentrically or coaxially along the guide wire has a longitudinal axis spaced from the reference edge a distance substantially equal to the distance from the tongue to a longitudinal axis of the lumen.
Yet another object of the present invention is to provide a method of arthroscopic anterior cruciate ligament reconstruction of the knee including forming a closed or open end femoral bone tunnel in the femur along a guide wire precisely positioned by a femoral guide inserted through a tibial bone tunnel from an anterolateral or anteromedial portal such that a longitudinal axis of the femoral bone tunnel is disposed 6-7 millimeters anterior to a posterior edge or xe2x80x9cover-the-top ridgexe2x80x9d of a notch on the femoral condyle.
Some of the advantages of the present invention are that accurate, isometric positioning of tibial and femoral bone tunnels in arthroscopic cruciate ligament reconstruction is enhanced, the time required to perform arthroscopic anterior cruciate ligament reconstruction is reduced, error in forming bone tunnels in arthroscopic cruciate ligament reconstruction is minimized, femoral bone tunnels can readily be located high in a notch formed in the femur, the use of blind, or closed-end, femoral bone tunnels as well as open-end femoral bone tunnels in arthroscopic anterior cruciate ligament reconstruction is permitted, the creation of a trough and not a tunnel when forming femoral bone tunnels is avoided, a cortical margin that is neither too wide nor too narrow is insured, tunnel placement can be verified prior to tunnel formation, the femoral isometric point can be accurately identified, the need for surgeons to estimate the position of drills and reamers when forming femoral bone tunnels along guide wires is eliminated, anteromedial and anterolateral portals can be used for inserting guide wires in arthroscopic anterior cruciate ligament reconstruction, the size of portals used in arthroscopic cruciate ligament reconstruction can be minimized, the femoral guide according to the present invention is streamlined in structure, right and left knee compatible and can be sterilized for repeated use, the tip of a guide wire positioned by the femoral guide on a bone surface can be viewed endoscopically, a footprint can be created on a bone surface as guided by a guide wire positioned by the femoral guide and examined prior to forming a bone tunnel allowing adjustments to be made if necessary, the femoral guide is designed to be accommodated in portals of very small size and the configuration of the femoral guide facilitates manipulation and maneuverability at the knee joint as well as arthroscopic visualization of the knee.
Accordingly, these and other objects and advantages are obtained with the present invention as characterized in a femoral guide including an elongate body having a distal end, a proximal end and a longitudinal lumen for receiving a guide wire and a handle mounting the proximal end of the body. The body includes a cylindrical member and a tip extending angularly, distally from the cylindrical member. The lumen extends through the cylindrical member from the proximal end toward the distal end, the lumen terminating distally at an opening on an arcuate surface of the tip, the opening being disposed proximally of the distal end. The lumen has a diameter sized to closely receive the outer diameter of a guide wire inserted through the femoral guide such that a longitudinal axis of the guide wire is substantially aligned with a longitudinal axis of the lumen, and the opening of the lumen allows the guide wire to protrude distally from the body to contact a bone surface. The arcuate surface of the tip terminates distally at an end wall at the distal end, and a tongue protrudes distally from the end wall and, therefore, the distal end, of the body. The tongue has a surface for engaging a reference edge on a surface of the bone, and the surface of the tongue is disposed a predetermined distance from the longitudinal axis of the lumen such that a guide wire inserted through the lumen will be positioned in contact with the bone surface a distance from the edge that is substantially equal to the predetermined distance. A stylus protrudes from the end wall in the same direction as the tongue allowing the stylus to be driven through the bone surface and into the bone with the bone surface abutting the end wall and the tongue engaging the reference edge. The guide wire can be driven into the bone along the lumen, and the femoral guide can be removed from the guide wire allowing an instrument, such as a cannulated drill or reamer, to be mounted on the guide wire with the guide wire extending through the cannulation to drill a tunnel in the bone substantially concentrically or coaxially along the guide wire such that a longitudinal axis of the tunnel is disposed from the reference edge substantially the predetermined distance. A method of forming bone tunnels endoscopically, or arthroscopically, in joints of the body such as the knee includes the steps of inserting the femoral guide at the joint through a portal of minimal size, positioning a tongue of the femoral guide in engagement with a reference edge on a surface of a bone of the joint, inserting a guide wire through a lumen of the femoral guide and contacting the bone surface with the guide wire at a location spaced from the edge a distance substantially equal to the distance from the tongue to a longitudinal axis of the lumens driving the guide wire into the bone through the lumen and forming a bone tunnel in the bone substantially concentrically or coaxially along the guide wire.